A cortisone injection is a mix of numbing medicine and a steroid. The injection is given directly to the area of pain, which is typically a joint. Once the medicine is in the joint, the numbing medication will ease the pain, while the steroid will reduce inflammation, pain, and swelling.
Some patients will get instant relief, while others will get relief in about 3–4 days after the injection. Best practices say that patients are able to have up to 4 injections in a year. But always check with your doctor.